Resin Rail Garnish Bends Absorb Thermal Distortion
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Solution Overview
Problem
The hermeticity between a vehicle body and door is compromised due to differing thermal expansion coefficients of metal and resin materials, leading to significant gap changes and potential interference when the vehicle is exposed to varying temperatures.
Innovation Solution
A rail garnish made of resin with strategically designed first and second bends, which extend along the longitudinal direction and are bent in different directions, is used to maintain contact with a seal member on the door, absorbing thermal distortion and preventing gap changes between the body and door, while a guide face and protrusion on the body guide the contact portion to maintain sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the body is constituted of resin to reduce weight, then weight reduction is achieved, but thermal distortion occurs differently between resin body parts and metal door, causing gap changes and hermeticity degradation
Solution Approach 1:
The rail garnish serves as an intermediary component between the body and door, absorbing thermal distortion through its bends to maintain proper sealing contact despite differential thermal expansion between resin body parts and metal door
Solution Approach 2:
The rail garnish utilizes changes in its geometric parameters (bend angles and shapes) in response to thermal distortion, allowing it to accommodate expansion and contraction while maintaining sealing effectiveness across temperature variations
2Adaptability or versatility
If the rail garnish is made of resin, then weight reduction and flexibility are achieved, but the rail garnish undergoes greater thermal distortion than the metal door, potentially causing contact portion to approach or move away from the door
Solution Approach 1:
The first and second bends in the rail garnish utilize curved geometries that allow the structure to flex and absorb thermal distortion, with the bends extending along the longitudinal direction and bending in different directions to counteract expansion forces
Solution Approach 2:
The rail garnish is divided into distinct functional segments (fixed portion, contact portion, and intermediate bends), allowing each segment to perform its specific function while the bends between them absorb thermal stresses
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively maintains hermeticity by absorbing thermal distortion in the rail garnish, preventing it from approaching or moving away from the door, thus maintaining a consistent gap and ensuring sealing integrity across temperature variations.
Implementation Method 1
when a temperature of the vehicle rises or falls, thermal distortion (thermal expansion or thermal contraction) may occur to each of the body and the door
Data Source
AI summary
A vehicle may include: a body including an opening; a door constituted of metal, the door being configured to open and close the opening; a rail garnish constituted of resin, the rail garnish being disposed along an edge of the opening; and a seal member disposed along an edge of the door and configured to seal a gap between the door and the body when the door closes the opening. The rail garnish may include a fixed portion, a contact portion, and a first bend and a second bend disposed between the fixed portion and the contact portion. The first bend and the second bend each may extend along the contact portion in a longitudinal direction of the rail garnish and are bent in different directions. A thickness of the rail garnish may be locally small at one or both of the first bend and the second bend.